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GM’s fuel-saving stop-start feature turns off the engine when the vehicle is not moving. But a whole list of trucks and SUVs won’t carry the feature anymore because of the global microchip shortage. Those pickups and SUVs with either the 5.3-liter or 6.2-liter V8 engines and 10-speed transmissions built after June 7 will cease to be equipped with the GM stop-start system. 

Those GM vehicles on the list include the 2021 Chevy Tahoe and Suburban, GMC Yukon and Yukon XL, Cadillac Escalade and Escalade ESV, and light-duty Chevy Silverado and GMC Sierra pickups. “By taking this measure, it will enable us to continue production of our high-demand full-size SUV and pickups as the industry continues to rebound and strengthen,” GM said in a statement.

Eliminating the stop-start feature reduces fuel economy in V8 engines

2021 Cadillac Escalade offers a 3.0L inline-six turbodiesel and gets an EPA-rated 23 MPG combined (2WD) | GM

Of course, the downside will be reduced fuel economy from those thirsty V8 engines. GM will give back $50 to offset the change. Unfortunately, the stop-start feature can’t be added later once microchip supplies return to normal. 

But GM does plan on adding it back into production once chip supplies strengthen. It also doesn’t expect that removing the feature will affect overall corporate average fuel economy numbers. 

This will now be the third year in recent years where fuel economy numbers will drop overall. In 2019 the number was 22.5 mpg, which was down from 23 mpg in 2018. In 2017 the EPA gave credits for complying with federal CAFE requirements. 

Besides stop-start GM also dropped active fuel management/dynamic fuel management

A 2021 GMC Sierra 1500 parked in a field
2021 GMC Sierra | GMC

According to Automotive News, GM already dropped the active fuel management/dynamic fuel management module back in March. This affected pickups with the 5.3-liter EcoTec3 V8 engine and either the six-speed or eight-speed automatic transmission. It reduced fuel economy in those trucks by one mile per gallon. 

This change was expected to run through the end of 2021 production which normally ends in August or September. It is unclear how long vehicles will be manufactured without the stop-start feature. “We routinely monitor our fleet for compliance in the U.S. and Canada, and we balance our portfolio in a way that enables us to manage unforeseeable circumstances like this without compromising our overall (greenhouse gas) and fuel economy compliance,” said spokesperson Michelle Malcho at the time. 

When will this whole chip shortage deal end?

Microchip supplies have somewhat improved as we enter the summer. But shortages are expected to linger through the rest of the production year. GM has been careful to shield big truck and SUV production from interruptions in production. It has stopped production for crossovers and vehicles like the Camaro which do not sell in the same numbers. 

As you can tell GM is doing everything it can to keep the assembly lines rolling for its full-size pickups and SUVs. But the adjustments it is making shows the severity of the whole chip shortage drama.


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